The smith's new puppy cries in the middle of the night. various family members periodically check the dog, who responds by happily wagging his tail. lately, his crying has actually increased. this increase is likely due to

positive reinforcement

Explanation:

Based on operant conditioning, positive reinforcement occurs when a behavior is reinforced by adding a particular stimulus which increase the chances of a behavior occuring again in the future . When a particular behavior is rewarded the response or that behavior is enhanced or strengthened. The dog cries and it is rewarded by the family constantly checking on it as a result the crying increases because the dog knows it will be comforted when it cries. The checking on the dog has increased the crying behavior

answer; proximity;

stable food supply,social structure, government,religion,culture/art,technology and writing/language;